The subject matter disclosed herein relates generally to detector assemblies used in environments containing explosive and/or combustible gases and/or vapors.
Environmental detection systems may include a variety of sensors for detecting the presence and/or concentration of various chemicals in various environments. For example, sensors may be used in hazardous environments for detecting the presence and/or concentration of hazardous (e.g., volatile, combustible, explosive, and/or toxic) gases and/or vapors.
At least some known detection systems are used in environments containing combustible and/or explosive gases and/or vapors. The sensors of such detection systems are typically mounted to a mounting structure having an explosion-resistant housing. The explosion-resistant housing has an interior chamber that is hermetically sealed to separate a volume of space within the housing from the environment. The sensors include one or more wires that connect a sensing element of the sensor to one or more processing components, power supply components, and/or communication components, each of which may be held within the interior chamber of the housing or further upstream. The wire(s) extend from the sensing element and pass through a body of the sensor into the interior chamber of the housing. The interior chamber of the housing is separated from the environment such that any combustion and/or explosion within the interior chamber is less likely to extend into the environment.
At least some known detection systems use heat-cured epoxy sealants to seal the wire(s) to the body of the sensor in an attempt to prevent any combustion and/or explosion within the interior chamber from extending into the environment through the interface between the wire(s) and the body of sensor (i.e., along the path of the wire(s) through the body of the sensor). But, such heat-cured epoxy sealants may lose adhesion to the body of the sensor over time, for example because of fatigue, environmental and/or chemical exposure, and/or different thermal expansion and contraction of the different materials of the epoxy and the body of the sensor. Moreover, heat-cured epoxy sealants may have tolerance issues with regard to the density and/or thermal coefficient of expansion of the epoxy, for example because of processing variations in material compounding, mixing, and/or post curing temperatures. The loss of adhesion and/or the tolerance issues of the heat-cured epoxy may cause the heat-cured epoxy to fail to maintain a seal at the interface between the wire(s) and the body of the sensor, which may enable an explosion and/or combustion within the interior chamber of the housing to extend into the environment. Accordingly, using a heat-cured epoxy sealant to seal the wire(s) to the body of the sensor may present safety issues in explosive and/or combustible environments.